Solid dielectric insulation materials are commonly used as insulation in electric power applications involving cables, accessories, transformers, power generators, power capacitors and the like, primarily to sustain the system voltage. Typical dielectric insulation materials include ethylene propylene diene monomer (EPDM) rubber, ethylene propylene rubber (EPR), and silicone. Medium and high voltage power cables typically comprise a conductor surrounded by a semiconductive layer and then a dielectric insulating layer to control the electric field around the conductor. Insulation materials also play the vital role of electrical stress control in cable accessories. Underground accessories, in particular, need to provide stress control in order to maintain and control the electrical stress below the breakdown level of the dielectric layer. As the dielectric breakdown strength of the dielectric material is increased, a thinner insulating layer is required for the cable or accessory to perform at the same voltage level. Cables and accessories that incorporate dielectric materials with increased dielectric breakdown strength can therefore be made smaller, lighter, and at a reduced cost in comparison to cable and accessories made with traditional insulating materials, with comparable voltage performance. This is especially important at transmission voltages, but is also important for medium voltage class cables and accessories.
As the demand for global electric power continues to rise, the need for improved medium and high voltage power components remains. Accordingly, there is a need for insulation materials having increased dielectric breakdown strength.